variavel0=<b>Fernando Cesar Ventura Pereira</b> - ventura@iae.cta.br Centro Técnico Aeroespacial
<b>Cláudio Martins de Oliveira</b> - claudioiae@iae.cta.br Instituto de Aeronautica e Espaço
<b>João Roberto Barbosa</b> - barbosa@mec.ita.cta.br Instituto Tecnológico de Aeronáutica
<b>Abstract.</b> The main aim of this work is to propose a methodology to define the geometrical parameters of a turbine and the gas dynamic parameters of a working fluid, which are able to substitute a real turbine of a liquid propellant rocket engine, that best equips the Brazilian Launcher Vehicle (VLS-2). To this goal, air, heated air, freon-12 and freon-22 were selected to substitute the combustion products of kerosene and liquid oxygen and their gas dynamics parameters were used to calculate the turbine geometry by a computer program based on an algorithm developed by Russian research Ovsyannikov. The performance of the four groups (working fluid and two-stage axial impulse turbine) was evaluated by another program that considered shaft rotational speed and total inlet pressure variations from 50% till 105% of their nominal values. Then, as a result of the analysis of the efficiency as a function of the ratio between tangential and absolute velocities, the author concluded that the working fluid is proper to simulate the real turbine of a liquid propellant rocket engine and the combustion products of kerosene and liquid oxygen, at 1000 K, in a test stand.
<b>Keywords.</b> turbine, rocket engine, liquid propulsion, numeric simulation.